"Tell me the things that really upset you about the new pope." -- This was said to me by a colleague from another university, an excellent scholar, who described herself as an atheist but also as "sympathetic" to Catholicism and as "someone who sees myself as a fellow-traveler." She just loved Francis: another manifestation of the so-called "Francis effect." I guess because I am supposed to be a "conservative" I am supposed to be irked by the pope (perhaps in the way that "liberals" were, or were supposed to have been, irked by Benedict).

I told her that I loved Francis as my spiritual father, that I found him wholly wonderful, and that -- if I even thought it appropriate for a believing Catholic to criticize a pope -- there was nothing at all that I found objectionable in what he said or did.

I'm not sure she believed that, and I could find nothing further to say to convince her, nothing to say in reply to her question, "What can you say to persuade me that Francis and Benedict have the same theology?"

But like many other such conversations, later on (in the inspiration which the French call "l'esprit d'escalier," a "staircase moment," when you think of something else just after you have left the party and are going upstairs to bed) it occurred to me that I could have made the case in the following way as well.

If only I had the Catechism of the Catholic Church before me -- I might have pointed to its 2,865 separate paragraphs, and its full 846 pages, in the latest print edition, and said, "Will you grant that Pope Francis assents to all of those points on all of those pages?"-- Because obviously Benedict and John Paul II before him agreed on all those points, as should all Catholics. What further agreement on theology or anything else could one want?

But it seemed to me that, really to reply to my friend's questions in a definitive way, it would help to find a core, some common belief which Francis and Benedict, and before them John Paul II, all emphasize as the primary and, in some sense, the sole thing which needs to be maintained. Is there such a thing? If so, what could that be?

Something that Francis said in a recent General Audience provided the key for me. "There is a celebrated saying by the French writer Leon Bloy, who, in the last moments of his life, said: 'The only real sadness in life is not becoming a saint.' Let us not lose the hope of holiness; let us follow this path. Do we want to be saints? The Lord awaits us, with open arms: he waits to accompany us on the path to sanctity."

In quoting Bloy, Pope Francis was saying in effect that holiness was success and happiness for a Christian, and "not becoming a saint" was failure and unhappiness for us. This seemed to be the core idea on which everything else hinged.

I found the same thing in Pope Benedict. You may remember that he devoted a series of talks at his General Audiences to the lives of saints. They make for excellent spiritual reading now. At the end of this series, Benedict turned to the theme of holiness in general. "We are all called to holiness: it is the very measure of Christian living," he taught, "I would like to ask all to open themselves to the action of the Holy Spirit, who transforms our life, to be, we too, small pieces in the great mosaic of holiness that God continues to create in history." Pope John Paul II, in his apostolic letter on the Church in the Third Millenium, famously taught too that, "The time has come to re-propose wholeheartedly to everyone this high standard of ordinary Christian living: the whole life of the Christian community and of Christian families must lead in [the] direction [of holiness]."

What one sees perhaps especially in Francis is an emphasis on the practical means of pursuing holiness: the detachment which comes from the love of poverty; the mercy we are shown when we show mercy. But Francis and Benedict agree too that holiness and the Christian life should be rooted in prayer.

In his audience about holiness, Benedict posed the question -- What is the absolute minimum necessary, so that one's striving after holiness amounts to more than a pipe dream? -- and he mentioned three things: "The essential means this: never leaving a Sunday without an encounter with the Risen Christ in the Eucharist; this is not an additional burden but is light for the whole week. It means never beginning and never ending a day without at least a brief contact with God. And, on the path of our life it means following the 'signposts' that God has communicated to us in the Ten Commandments, interpreted with Christ, which are merely the explanation of what love is in specific situations." So practically speaking, the Eucharist, daily prayer, and following the commandments are the essentials.

Pope Francis recently concretized this idea of "a brief contact with God," for instance, by asking those present at his General Audience to carry a small New Testament and read brief excerpts from it throughout the day. This is just one example. Pay close attention to him, and you will find lots of others.

Michael Pakaluk is chairman and professor of philosophy at Ave Maria University.